The use of valve assemblies in filters is wide spread particularly in heavy duty diesel engines and the like. The valve assembly permits the liquid (e.g., water) which has accumulated in the lower portion of the filter housing or vessel to be periodically drained. Such prior valve assemblies for this purpose, however, because of their design characteristics are beset with one or more of the following shortcomings: (a) the assembly is of a complex and costly construction; (b) the assembly is possessed of an inordinate number of components thereby making the assembly difficult and awkward to install on the filter vessel; (c) substantial manual manipulation of one of the components is required in order to effect drainage or to discontinue drainage through the valve assembly; and (d) the prior structure is provided with a liquid level sensor which is a separate entity and is not integrated with a functional component of the valve assembly.